Gas compressor

ABSTRACT

A back pressure space of a vane groove having completed communication with an intermediate-pressure supply groove communicates with a first supply section until refrigerant pressure in each of compression chambers having been partitioned by vanes of the vane grooves reach the highest pressure, and then high pressure is supplied from the first supply section. At a time point when the back pressure space having completed communication with an intermediate-pressure supply groove communicates with the first supply section of a high-pressure supply groove, the preceding back pressure space adjacent to that back pressure space on the downstream side of the rotation direction completes communication with the first supply section.

TECHNICAL FIELD

The present invention relates to a so-called vane rotary-type gascompressor.

BACKGROUND ART

Conventionally, various gas compressors have been proposed as indicatedin Patent Literature 1.

FIG. 16 shows a compression block disposed in a gas compressorpertaining to Patent Literature 1.

This compression block has a cylinder block 100 and a pair of sideblocks 101 disposed on the left and right of the cylinder block 100. Acylinder chamber 105 is formed in the cylinder block 100 and the pair ofthe side blocks 101. The cylinder block 100 is provided with a suctionport 110 and two discharge ports 108.

A rotor 102 is rotatably disposed in the cylinder chamber 105. The rotor102 is formed with a plurality of vane grooves 106 at intervals. A vane103 is disposed in each vane groove 106 so as to freely retractable froman outer peripheral surface of the rotor 102. A back pressure space 107(107A, 107B and 107C) is formed in the vane groove 106 on the backsurface side of the vane 103. The back pressure space 107 opens to bothside surfaces of the rotor 102.

An intermediate-pressure supply groove 113 and a high-pressure supplygroove 114 are formed in a wall surface on the cylinder chamber 105 sideof each side block 101, on a rotation locus of the back pressure space107. An intermediate pressure that is a pressure higher than that of asucked refrigerant and is lower than that of the discharged refrigerantis supplied to the intermediate-pressure supply groove 113. Highpressure that is a pressure equivalent to that of the dischargedrefrigerant is supplied to the high-pressure supply groove 114.

Compression chambers 105 a, 105 b and 105 c are formed in the cylinderchamber 105 by being surrounded by the two vanes 103. The compressionchambers 105 a, 105 b and 105 c perform a suction process, a compressionprocess and a discharged process and repeat this series of theprocesses, at the time of rotation of the rotor 102.

In the suction process, the refrigerant is sucked from the suction port110 by gradual increase in volumes of the compression chambers 105 a,105 b and 105 c. In the compression process, the refrigerant iscompressed by gradual decrease in volumes of the compression chambers105 a, 105 b and 105 c. In the discharged process, when the volumes ofthe compression chambers 105 a, 105 b and 105 c are gradually decreasedand a refrigerant pressure becomes at least a predetermined pressure, anopen/close valve 109 opens and the refrigerant is discharged from thedischarge port 108.

In such a series of processes, as to each of the vane 103, although therefrigerant pressures in the compression chambers 105 a, 105 b and 105 cpress each of the vanes 103 in a direction (hereinafter, a “storagedirection”) in which each of the vane 103 is stored in the vane groove106, a tip of each of the vane 103 slides along an inner wall of thecylinder chamber 105 by a back pressure acting on the back pressurespace 107 and thereby the compression chambers 105 a, 105 b and 105 care able to reliably compress the refrigerant.

Here, in the suction process and in an early stage of the compressionprocess in which pressure in the storage direction is small, anintermediate pressure from the intermediate-pressure supply groove 113is made to act as the back pressure. In addition, in a later stage ofthe compression process and in the discharged process in which thepressure in the storage direction of the vane 103 is large, highpressure from the high-pressure supply groove 114 is made to act as theback pressure. In this way, a sliding resistance of the vane 103 is madeas small as possible so as to achieve low fuel consumption by changingthe back pressure made to act on the vane 103, in accordance with thepressure in the storage direction of the vane 103.

CITATION LIST Patent Literature

Patent Literature 1: Japanese Patent Laid-Open Publication No.2013-194549

SUMMARY OF INVENTION Technical Problem

FIG. 17 is a graph showing changes in a pressure P105 a in thecompression chamber 105 a, a pressure P105 b in the compression chamber105 b and a pressure P107A in the back pressure space 107A in accordancewith a rotation angle of the rotor. As shown in FIG. 17, at an angle of180 degrees, the back pressure space 107A having completed communicationwith the intermediate-pressure supply groove 113 communicates with thehigh-pressure supply groove 114.

In the example shown in FIG. 16, when the back pressure space 107Bshifts a communication state from the intermediate-pressure supplygroove 113 to the high-pressure supply groove 114, the precedingrotation downstream back pressure space 107A is already in communicationwith the high-pressure supply groove 114. Accordingly, when thefollowing rotation upstream back pressure space 107B completes shiftingof the communication state to the high-pressure supply groove 114, thetwo back pressure spaces 107A and 107B are simultaneously brought into astate of communicating with the high-pressure supply groove 114.

Since the pressure P107B in the rotation upstream back pressure space107B is intermediate pressure, the pressure P107A in the rotationdownstream back pressure space 107A that communicates with the rotationupstream back pressure space 107B via the high-pressure supply groove114 becomes temporarily lower than a pressure to be supplied to thehigh-pressure supply groove 114 as shown by P in FIG. 17. Since, in thevane 103 on the rotation downstream side, the pressures of therefrigerant in the compression chambers 105 a, 105 b and 105 c which arein the later stage of the compression process and in the dischargedprocess act in the storage direction of the vane 103, there is apossibility that the vane 103 may be temporarily stored in the vanegroove 106 and chattering may occur.

The present invention has been made in view of the above-mentionedcircumstances and an object of the present invention is to preventoccurrence of chattering of the vane by a temporary reduction inpressure in the back pressure space of the vane, for example, in thelater stage of the compression process and in the discharged process,and to maintain operating performance as a gas compressor.

Solution to Problem

In order to achieve the above-mentioned object, a gas compressor of thepresent invention includes:

a tubular cylinder block having therein a cylinder chamber in which arefrigerant is compressed;

side blocks that are attached to side parts of the cylinder block andseal an opening of the cylinder chamber on the side parts;

a rotor that rotates in the cylinder chamber and has a plurality of vanegrooves opening to an outer peripheral surface facing an innerperipheral surface of the cylinder chamber at intervals in a rotationdirection;

a plurality of vanes that is respectively stored in the respective vanegrooves, protrudes and retracts from the outer peripheral surface, comesinto sliding contact with the inner peripheral surface of the cylinderchamber, and partitions a space between the inner peripheral surface andthe outer peripheral surface of the rotor into a plurality ofcompression chambers;

an intermediate-pressure supply section that is formed in at least oneof the side blocks, communicates with a back pressure space at a groovebottom of each of the vane grooves storing the vanes for partitioningthe compression chambers from a suction process to a compressionprocess, and supplies, to the back pressure space, an intermediatepressure larger than a refrigerant pressure in each of the compressionchambers from the suction process to the compression process; and

a high-pressure supply section that is formed in at least one of theside blocks, communicates with the back pressure space in each of thevane grooves storing the vanes for partitioning the compression chambersfrom the compression process to a discharged process after communicationwith the intermediate-pressure supply section has been completed, andsupplies, to the back pressure space, high pressure larger than therefrigerant pressure in each of the compression chambers from thecompression process to the discharged process and larger than theintermediate pressure, wherein

the high-pressure supply section is divided into a plurality of mutuallyindependent supply sections in the rotation direction,

the second supply section that is positioned at least secondarily fromthe most upstream side in the rotation direction is formed into a shapein which the second supply section, while communicating with the backpressure space of one vane groove, does not simultaneously communicatewith the back pressure space of the other vane groove adjacent to thevane groove on the upstream side in the rotation direction, and thehigh-pressure supply section is formed in a range in which itsimultaneously communicates with the back pressure space of the one vanegroove and the back pressure space of the other vane groove adjacent tothe vane groove on the upstream side in the rotation direction.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional diagram showing an overall configuration ofa vane rotary-type gas compressor according to a first embodiment of thepresent invention.

FIG. 2 is a cross-sectional diagram along the I-I line of the gascompressor in FIG. 1.

FIG. 3 is a cross-sectional diagram along the II-II line of the gascompressor in FIG. 1.

FIG. 4 is an explanatory diagram showing essential parts of acompression block shown in FIG. 3, in an enlarged manner.

FIG. 5 is an explanatory diagram showing a virtual example of a casewhere a first supply section and a second supply section of ahigh-pressure supply groove in FIG. 3 are disposed apart from each otherat an interval at which a back pressure space of a vane groove does notcommunicate with any of them.

FIG. 6 is a graph showing changes in pressure in the compression chamberand pressure in the back pressure space of the vane in the vane groovein FIG. 5, in accordance with a rotation angle of a rotor.

FIG. 7 is an explanatory diagram showing a communication cross-sectionalarea between the first supply section of the high-pressure supply grooveand the back pressure space in the vane groove, and a communicationcross-sectional area between the second supply section of thehigh-pressure supply groove and the back pressure space in the vanegroove, in FIG. 3.

FIG. 8 is a graph showing changes in the pressure in the compressionchamber and the pressure in the back pressure space of the vane in thevane groove in FIG. 3 in accordance with the rotation angle of therotor.

FIG. 9 is a cross-sectional diagram of a vane rotary-type gas compressoraccording to a second embodiment of the present invention, at a positioncorresponding to the cross-sectional diagram in FIG. 2.

FIG. 10 is a cross-sectional diagram of the vane rotary-type gascompressor according to the second embodiment of the present invention,at a position corresponding to the cross-sectional diagram in FIG. 3.

FIG. 11 is an explanatory diagram showing essential parts of acompression block shown in FIG. 10 in an enlarged manner.

FIG. 12 is an explanatory diagram showing a positional relation betweena region in which a projection stroke of the vane relative to the vanegroove is reduced at a rate equal to or more than a constant level andan interval between the first supply section and the second supplysection in the compression block shown in FIG. 10.

FIG. 13 is a graph showing changes in the pressure in the compressionchamber and the pressure in the back pressure space in the vane groovein FIG. 12 in accordance with the rotation angle of the rotor.

FIG. 14 is an explanatory diagram showing a positional relation, duringa period when the vane is in sliding contact with a region in which theprojection stroke of the vane relative to the vane groove is reduced ata rate equal to or more than a constant level, between the regionconcerned and an interval between the first supply section and thesecond supply section, in the compression block shown in FIG. 10.

FIG. 15 is a graph showing changes in the pressure in compressionchamber and the pressure in the back pressure space of the vane in thevane groove in FIG. 10 in accordance with the rotation angle of therotor.

FIG. 16 is an explanatory diagram showing an inside of a compressionblock of a conventional gas compressor.

FIG. 17 is a graph showing changes in pressure in a compression chamberand pressure in a back pressure space of a vane in a vane groove in FIG.16 in accordance with the rotation angle of the rotor.

DESCRIPTION OF EMBODIMENTS First Embodiment

The first embodiment of the present invention will be described withreference to FIG. 1 to FIG. 8.

As shown in FIG. 1, a gas compressor 1 according to the presentembodiment includes a substantially cylindrical housing 2, a compressionsection 3 stored in the housing 2, a motor section 4 that transmitsdriving force to the compression section 3 and an inverter section 5which is fixed to the housing 2 and which controls driving of the motorsection 4.

The housing 2 is configured by a front head 7 in which a not shownsuction port is formed and a bottomed cylindrical rear case 9 whoseopening is closed by the front head 7.

The compression section 3 is fixed to an inner wall 13 of the rear case9. The compression section 3 is formed with a suction chamber 11 on oneside and is formed with a discharge chamber 15 on the other side so asto partition the inside of the housing 2. In addition, a not showndischarge port which communicates the discharge chamber 15 with arefrigerating cycle is formed in an outer periphery of the rear case 9.Additionally, an oil sump 17 which stores an oil O for maintaininglubricity of the compression section 3 is formed under the dischargechamber 15.

The compression section 3 includes a compression block 19 that forms acylinder chamber 33, an oil separator 21 fixed to the compression block19, a rotor 23 that is rotatably stored in the cylinder chamber 33, avane 25 (refer to FIG. 3) that protrudes and retracts from the rotor 23to partition the cylinder chamber 33, and a drive shaft 27 that is fixedintegrally with the rotor 23 to transmit the driving force thereto.

The compression block 19 is configured by a cylinder block 29, a pair ofside blocks 31, and the cylinder chamber 33 formed on an inner peripheryof the cylinder block 29.

As shown in FIG. 3, the cylinder block 29 has the distorted ellipticalcylinder chamber 33 therein. An opening of this cylinder chamber 33 isclosed by holding both ends of the cylinder block 29 by the pair of theside blocks 31.

As shown in FIG. 3 and FIG. 4, the rotor 23 is disposed such that oneplace is in contact with an inner wall of the cylinder chamber 33, isdisposed with a position displaced from the center (the center ofgravity) of the cylinder chamber 33 being set as the center of rotation,and is provided with a vane groove 75 that opens to an outer peripheralsurface of the rotor 23, and a back pressure space 77 on the backsurface side of the vane 25.

The cylinder chamber 33 is partitioned into a plurality of pieces in arotation direction X of the rotor 23 by the plurality of vanes 25 thatprotrudes and retracts from the plurality of vane grooves 75 in therotor 23. Thereby, a plurality of compression chambers 33 a, 33 b and 33c is formed between an inner peripheral surface 33 d of the cylinderchamber 33 and an outer peripheral surface 23 a of the rotor 23.

In addition, the cylinder block 29 is provided with a suction slot 39through which the refrigerant is sucked into the cylinder chamber 33, adischarge slot 35 through which the refrigerant having been compressedin the cylinder chamber 33 is discharged, an open/close valve 37 whichopens/closes the discharge slot 35 and a cylinder-side oil supply path41 which communicates with an oil supply path of the side block 31.

As shown in FIG. 1, the pair of the side blocks 31 are configured by afront-side block 31 a and a rear-side block 31 b and the oil separator21 is fixed to the rear-side block 31 b.

The front-side block 31 a is provided with a front-side end surface 43that abuts on the cylinder block 29, a not shown suction slot thatcommunicates with the suction slot 39 and sucks the refrigerant from thesuction chamber 11, a front-side bearing 47 that rotatably supports thedrive shaft 27 and a front-side oil supply path 49 that communicateswith the cylinder-side oil supply path 41.

The front-side end surface 43 is provided with a pressure supply groove,and the pressure supply groove includes an intermediate-pressure supplygroove 51 that supplies, to the back pressure space 77, an intermediatepressure (a middle pressure) higher than that of the sucked refrigerantand lower than that of the discharged refrigerant and a high-pressuresupply groove 53 that is provided at a position facing a high-pressuresupply groove 69 on the rear-side block 31 b side.

In addition, the front-side bearing 47 is formed with an annularfront-side annular groove 55, which is provided in communication withthe one-end side of the front-side oil supply path 49. Note that theother-end side of the front-side oil supply path 49 is in communicationwith the cylinder-side oil supply path 41.

As shown in FIG. 2, the rear-side block 31 b includes a rear-side endsurface 57 that abuts on the cylinder block 29, an oil supply hole 59through which the oil O stored under the discharge chamber 15 is sucked,a rear-side bearing 63 that rotatably supports the drive shaft 27, and arear-side oil supply path 59 b that communicates with the cylinder-sideoil supply path 41.

The rear-side end surface 57 includes a discharge hole 61 through whichthe refrigerant having been compressed in the cylinder chamber 33 isdischarged, an intermediate-pressure supply groove 67 (corresponding toan intermediate-pressure supply section in the claims) which supplies,to the back pressure space 77, the oil of intermediate pressure higherthan pressure (suction pressure) of the sucked refrigerant and lowerthan pressure (discharged pressure) of the discharged refrigerant, andthe high-pressure supply groove 69 (corresponding to a high-pressuresupply section in the claims) which supplies, to the back pressure space77, the oil of high pressure that is the pressure (the dischargepressure) of the discharged refrigerant.

The high-pressure supply groove 69 is divided into mutually independentfirst supply section 69 a (corresponding to an upstream-side supplysection) and second supply section 69 b (corresponding to adownstream-side supply section) in the rotation direction X of the rotor23.

In addition, high-pressure supply paths 71 a and 71 b respectively opento the first supply section 69 a and the second supply section 69 b, andthe respective high-pressure supply paths 71 a and 71 b are incommunication with a rear-side annular groove 73 on their one-end sidesand are in communication with the first supply section 69 a and thesecond supply section 69 b, respectively, on their other-end sides.

Note that the high-pressure supply groove 53 of the front-side block 31a facing the high-pressure supply groove 69 is also divided into twosupply sections (not shown) which are similar to the first supplysection 69 a and the second supply section 69 b.

The back pressure space 77 (refer to FIG. 3 and FIG. 4) formed in therotor 23 communicates with the intermediate-pressure supply grooves 51and 67 at a compression first-half position and communicates with thehigh-pressure supply grooves 53 and 69 at a compression later-halfposition, by rotation of the rotor 23.

In a state shown in FIG. 4, a back pressure space 77B of the vane groove75 in a vane 25B which partitions the compression chamber 33 b havingmoved from a suction process to a compression process and thecompression chamber 33 a that is positioned on the downstream side ofthe compression chamber 33 b in the rotation direction X of the rotor 23and has moved from the compression process to a discharged process byrotation of the rotor 23 terminates communication with theintermediate-pressure supply groove 67. Then, the back pressure space77B is about to communicate with the first supply section 69 a that ispositioned on the upstream side of the rotation direction X of the rotor23, from now on.

In this state, a back pressure space 77A of the vane groove 75 in a vane25A that precedes the vane 25B in the downstream side of the vane 25B inthe rotation direction X of the rotor 23 has already completedcommunication with the first supply section 69 a and is in communicationwith the second supply section 69 b positioned on the downstream side inthe rotation direction X.

In addition, in the rotation direction X of the rotor 23, the firstsupply section 69 a is formed into a shape in which the back pressurespace 77A of the preceding vane 25A and the back pressure space 77B ofthe next vane 25B that follows the vane 25A do not communicate with thefirst supply section 69 a simultaneously. Namely, in the rotationdirection X of the rotor 23, the first supply section is formed suchthat an angle range in which the first supply section 69 a extendsbecomes smaller than a difference between the angle at which the backpressure space 77A is positioned and the angle at which the backpressure space 77B is positioned. In short, a distance between the backpressure space 77A and the back pressure space 77B in the rotationdirection X of the rotor 23 is set larger than a width of the firstsupply section 69 a.

In a similar way, in the rotation direction X of the rotor 23, thesecond supply section 69 b is formed into a shape in which the backpressure space 77A of the preceding vane 25A and the back pressure space77B of the next vane 25B that follows the vane 25A do not communicatewith the second supply section 69 b simultaneously. Namely, in therotation direction X of the rotor 23, the second supply section isformed such that an angle range in which the second supply section 69 bextends becomes smaller than the difference between the angle at whichthe back pressure space 77A is positioned and the angle at which theback pressure space 77B is positioned. In short, the distance betweenthe back pressure space 77A and the back pressure space 77B in therotation direction X of the rotor 23 is set larger than a width of thesecond supply section 69 b.

As described above, restrictions are caused on the angle range in whichthe first supply section 69 a extends and the angle range in which thesecond supply section 69 b extends, on the basis of the differencebetween the angle at which the back pressure space 77A is positioned andthe angle at which the back pressure space 77B is positioned.

Similarly, restrictions are caused on the angle range in which the firstsupply section 69 a extends and the angle range in which the secondsupply section 69 b extends, on the basis of a difference between theangle at which the back pressure space 77B is positioned and an angle atwhich a back pressure space 77C is positioned.

Likewise, restrictions are caused on the angle range in which the firstsupply section 69 a extends and the angle range in which the secondsupply section 69 b extends, on the basis of a difference between theangle at which the back pressure space 77C is positioned and the angleat which the back pressure space 77A is positioned.

In this way, the shapes of the first supply section 69 a and the secondsupply section 69 b are determined on the basis of the angle at whichthe back pressure space 77 is positioned in the rotation direction X ofthe rotor 23.

Note that a distance between the intermediate-pressure supply groove 67and the first supply section 69 a and a distance between the secondsupply section 69 b and the intermediate-pressure supply groove 67 inthe rotation direction X of the rotor 23 are set larger than a width ofthe back pressure space 77 in the rotation direction X of the rotor 23.

As shown in FIG. 1, the oil supply hole 59 is formed in communicationwith a rear-side oil supply path 59 a, and the rear-side oil supply path59 b is formed by branching from the rear-side oil supply path 59 a. Therear-side oil supply path 59 b is in communication with thecylinder-side oil supply path 41.

The rear-side bearing 63 is formed with the annular rear-side annulargroove 73, which is in communication with a rear-side communication path65. The rear-side communication path 65 is in communication with therear-side annular groove 73 on its one-end side and opens to thehigh-pressure supply groove 69 on its other-end side.

The oil separator 21 is fixed to the rear-side block 31 b, therefrigerant having been compressed in the cylinder chamber 33 flows intothe oil separator 21, and the refrigerant and the oil O are separatedfrom each other therein.

The drive shaft 27 is fixed to the rotor 23 on its one side and isrotatably supported by the bearings 47 and 63 of the respective sideblocks 31 a and 31 b. In addition, the motor section 4 is fixed to theother side of the drive shaft 27.

The motor section 4 includes a stator 79 fixed to the inner wall 13 ofthe rear case 9 and a motor rotor 81 that is rotatably disposed on theinner periphery side of the stator 79 and rotates by a magnetic force.The motor rotor 81 transmits a rotational drive force to the compressionsection 3, due to the rotation by the magnetic force.

Here, there will be described an interval between the first supplysection 69 a and the second supply section 69 b of the high-pressuresupply groove 69 in the rotation direction X of the rotor 23.

In the present embodiment, as shown in FIG. 3 and FIG. 4, the distancebetween the first supply section 69 a and the second supply section 69 bin the rotation direction X of the rotor 23 is set narrower than thewidth of the back pressure space 77 in the rotation direction X of therotor 23.

Here, as shown in FIG. 5, it is assumed that the interval between thefirst supply section 69 a and the second supply section 69 b of thehigh-pressure supply groove 69 in the rotation direction X of the rotor23 is wider than the width of the back pressure space 77. FIG. 5 is anexplanatory diagram showing a virtual example of a case where the firstsupply section and the second supply section of the high-pressure supplygroove in FIG. 3 are separately disposed at an interval at which theback pressure space of the vane groove does not communicate with any ofthem.

FIG. 6 is a graph showing changes in a pressure P33 a in the compressionchamber 33 a, a pressure P33 b in the compression chamber 33 b and apressure P77B of the back pressure space 77B, in accordance with arotation angle of the rotor. As shown in FIG. 6, at an angle of 180degrees, the back pressure space 77B having completed communication withthe intermediate-pressure supply groove 67 communicates with thehigh-pressure supply groove 69. In the present embodiment, thehigh-pressure supply groove 69 is constituted by the first supplysection 69 a and the second supply section 69 b, and the back pressurespace 77B communicates with the first supply section 69 a and thereaftercommunicates with the second supply section 69 b, along with rotation ofthe rotor 23 that rotates in the rotation direction X.

Since the interval between the first supply section 69 a and the secondsupply section 69 b of the high-pressure supply groove 69 in therotation direction X of the rotor 23 is larger than the width of theback pressure space 77B, there is generated a state where the backpressure space 77B does not communicate with any of the first supplysection 69 a and the second supply section 69 b when a communicationdestination of the back pressure space 77B shifts from the first supplysection 69 a to the second supply section 69 b.

At this time, the vane 25B stored in the vane groove 75, the backpressure space 77B of which is positioned between the first supplysection 69 a and the second supply section 69 b, receives force actingin a direction of intruding into the vane groove 75 from the innerperipheral surface 33 d of the cylinder chamber 33 since the compressionchambers 33 a and 33 b partitioned by the vane 25B stay from the laterstage of the compression process to the discharged process. Namely, whenthe back pressure space 77B is positioned between the first supplysection 69 a and the second supply section 69 b, the volume of the backpressure space 77B is in a state of being reduced.

However, since the back pressure space 77B does not communicate with anyof the first supply section 69 a and the second supply section 69 b atthis position, it is not possible to release the high pressure of theamount corresponding to the reduced volume of the back pressure space77B to any place other than the back pressure space 77B. Accordingly, inthe middle stage of shifting the communication destination of the backpressure space 77B from the first supply section 69 a to the secondsupply section 69 b, the pressure in the back pressure space 77temporarily rises as shown by P1 in FIG. 6. Namely, since there isgenerated a state where the back pressure space 77B is not in acommunication state with any of the first supply section 69 a and thesecond supply section 69 b, the pressure in the back pressure space 77temporarily rises as shown by P1 in FIG. 6.

When such a pressure rise in the back pressure space 77B is generated,the vane 25B which is receiving force of the direction of intruding intothe vane groove 75 from the inner peripheral surface 33 d of thecylinder chamber 33 attempts to project from the vane groove 75 by therisen pressure in the back pressure space 77B. Then, there is apossibility that pressing force of the vane 25B against the innerperipheral surface 33 d of the cylinder chamber 33 may be increased morethan necessary and the sliding resistance between the vane 25B and theinner peripheral surface 33 d of the cylinder chamber 33 may beincreased.

The similar phenomenon to the above can be generated in a state wherethe vane 25A and a vane 25C are not in communication with any of thefirst supply section 69 a and the second supply section 69 b.

Accordingly, in the gas compressor 1 of the present embodiment, as shownin FIG. 7, when the communication destination of the back pressure space77 is shifted from the first supply section 69 a to the second supplysection 69 b, there is ensured, by a fixed amount or more, across-sectional area obtained by summing up a communicationcross-sectional area Si between the back pressure space 77 and the firstsupply section 69 a and a communication cross-sectional area S3 betweenthe back pressure space 77 and the second supply section 69 b.

Specifically, when the back pressure space 77 is in communication withthe first supply section 69 a and the second supply section 69 b, it ispossible to release the high pressure in the back pressure space 77 tothe high-pressure supply paths 71 a and 71 b through which the highpressure oil O is supplied to the first supply section 69 a and thesecond supply section 69 b, and the rear-side communication path 65continued to the high-pressure supply paths 71 a and 71 b, the rear-sideannular groove 73, the rear-side oil supply path 59 a, and the oilsupply hole 59.

In order to ensure a high-pressure release route which is equal to orbetter than the above, in the gas compressor 1 of the presentembodiment, an interval at which the total of the above-mentionedcommunication cross-sectional areas Si and S3 becomes at least a minimumpath cross-sectional area in a high-pressure oil O supply route for thefirst supply section 69 a and the second supply section 69 b, from thehigh-pressure supply paths 71 a and 71 b down to the oil supply hole 59,is provided between the first supply section 69 a and the second supplysection 69 b in the rotation direction X of the rotor 23.

Next, an operation of the gas compressor 1 according to the presentembodiment will be described.

First, an electric current flows through a coil having been wound on thestator 79 of the motor section 4 by control of the inverter section 5shown in FIG. 1. Magnetic force is generated by electric current flowingthrough the coil, and the motor rotor 81 disposed on the inner peripheryof the stator 79 rotates.

The drive shaft 27 on the one-end side of which the motor rotor 81 isfixed rotates by rotation of the motor rotor 81, and also the rotor 23which is fixed on the other-end side of the drive shaft 27 rotates.

The refrigerant flows into the suction chamber 11 together with rotationof the rotor 23, and the refrigerant is sucked into the cylinder chamber33 from the suction chamber 11 via a suction slot (not shown) of thefront-side block 31 a (the suction process). The refrigerant having beensucked into the cylinder chamber 33 enters the compression chambers 33a, 33 b and 33 c formed in the cylinder chamber 33 by the plurality ofvanes 25, and thereby the refrigerant in the compression chambers 33 a,33 b and 33 c is compressed by rotation of the rotor 23 (the compressionprocess).

The refrigerant having been compressed in the cylinder chamber 33 pushesthe open/close valve 37 open, and is discharged from the discharge slot35 (the discharged process) and is discharged from the discharge hole 61into the discharge chamber 15 via the oil separator 21. In addition, therefrigerant having been discharged from the discharge hole 61 isseparated into the refrigerant and the oil O by the oil separator 21,the refrigerant is discharged from a not shown discharge port to the notshown refrigerating cycle, and the oil O is stored under the dischargechamber 15.

The oil having been stored under the discharge chamber 15 is suppliedfrom the oil supply hole 59 in the rear-side block 31 b to the rear-sidebearing 63 through the rear-side oil supply path 59 a.

The high-pressure oil having been supplied to the rear-side bearing 63is reduced to intermediate pressure higher than the pressure (thesuction pressure) of the sucked refrigerant and lower than the pressure(the discharged pressure) of the discharged refrigerant, by beingsqueezed between the rear-side bearing 63 and the drive shaft 27, andthe oil O having been reduced to the intermediate pressure is suppliedto the intermediate-pressure supply groove 67 through a gap between thedrive shaft 27 and the rear-side block 31 b.

The intermediate pressure oil O having been supplied to theintermediate-pressure supply groove 67 supplies the intermediatepressure to the back pressure space 77 and supplies the intermediatepressure to the back surface of the vane 25 such that the vane 25projects from the vane groove 75, over a range from the refrigerantsuction process to the compression process as shown in FIG. 3.

In addition, the high-pressure oil O having been supplied to therear-side bearing 63 is supplied from the high-pressure supply paths 71a and 71 b opening to the rear-side end surface 57 to the first supplysection 69 a and the second supply section 69 b of the high-pressuresupply groove 69, via the rear-side communication path 65.

The high-pressure oil O having been supplied to the first supply section69 a and the second supply section 69 b supplies the high pressure tothe back pressure space 77 and supplies the high pressure to the backsurface of the vane 25 such that the vane 25 projects from the vanegroove 75, over a range from the refrigerant compression process to thedischarged process as shown in FIG. 3. In addition, the first supplysection 69 a and the second supply section 69 b communicate with the notshown respective corresponding supply sections of the high-pressuresupply groove 53 on the front-side block 31 a side via the back pressurespace 77, and the high pressure is also supplied from each of the supplysections of the high-pressure supply groove 53 to the back pressurespace 77.

Furthermore, the high-pressure oil O flows into the rear-side oil supplypath 59 a from the oil supply hole 59, passes through the rear-side oilsupply path 59 b by being branched from the rear-side oil supply path 59a, and is supplied from the front-side oil supply path 49 to thefront-side bearing 47 via the cylinder-side oil supply path 41.

The high-pressure oil O having been supplied to the front-side bearing47 has intermediate pressure by being squeezed between the front-sidebearing 47 and the drive shaft 27, and the oil O having been reduced tothe intermediate pressure is supplied to the intermediate-pressuresupply groove 51 through the gap between the drive shaft 27 and thefront-side block 31 a.

The high-pressure oil O having been supplied from the high-pressuresupply grooves 53 and 69 of the front-side block 31 a and the rear-sideblock 31 b is supplied to the back pressure space 77 of the rotor 23 ata rotation latter-half position of the rotor 23 to impart the backpressure for making the vane 25 project from the vane groove 75.

According to the gas compressor 1 of the present embodiment, the backpressure space 77 of the vane groove 75 having completed communicationwith the intermediate-pressure supply groove 67 communicates with thefirst supply section 69 a of the high-pressure supply groove 69, and thehigh pressure is supplied from the first supply section 69 a thereto.

Thereafter, this back pressure space 77 completes communication with thefirst supply section 69 a before the back pressure space 77 of the nextvane groove 75 that is positioned on the upstream side of the rotationdirection X communicates with the first supply section 69 a andcommunicates with the second supply section 69 b that is independent ofthe first supply section 69 a and is positioned on the downstream sideof the rotation direction X, and thus the high pressure is againsupplied to the back pressure space.

Accordingly, at a time point when the back pressure space 77 havingcompleted communication with the intermediate-pressure supply groove 67communicates with the first supply section 69 a of the high-pressuresupply groove 69, the preceding back pressure space 77 adjacent to theback pressure space 77 on the downstream side in the rotation directionX does not communicate with the first supply section 69 asimultaneously.

In FIG. 4, there is shown a situation in which the back pressure space77A completes communication with the first supply section 69 a beforethe back pressure space 77B of the next vane groove 75 that ispositioned on the upstream side in the rotation direction X communicateswith the first supply section 69 a and communicates with the secondsupply section 69 b that is independent of the first supply section 69 aand is positioned on the downstream side in the rotation direction X,and thus the high pressure is again supplied to the back pressure space77A.

Accordingly, the preceding back pressure space 77A adjacent to the backpressure space 77B on the downstream side in the rotation direction Xdoes not communicate with the first supply section 69 a simultaneouslyat a time point when the back pressure space 77B communicates with thefirst supply section 69 a of the high-pressure supply groove 69. Thesimilar relation is established not only between the back pressure space77A and the back pressure space 77B, but also between the back pressurespace 77B and the back pressure space 77C, and between the back pressurespace 77C and the backpressure space 77A.

It is possible to prevent the pressure in the preceding back pressurespace 77 from being temporarily lowered from the high pressure by theintermediate pressure before the following next back pressure space 77rises to the high pressure, by allowing the two back pressure spaces 77not to communicate with the first supply section 69 a simultaneously.Accordingly, it is possible to prevent the occurrence of chattering inwhich the vane 25 repeats contact with and separation from the innerperipheral surface 33 d of the cylinder chamber 33, by a temporaryreduction of pressure in the back pressure space 77 of the vane 25 inthe early stage of the compression process.

Furthermore, the back pressure space 77 completes communication with thesecond supply section 69 b before the back pressure space 77 of the nextvane groove 75 which is positioned on the upstream side in the rotationdirection X communicates with the second supply section 69 b.Accordingly, at a time point when the back pressure space 77 havingcompleted communication with the first supply section 69 a of thehigh-pressure supply groove 69 communicates with the second supplysection 69 b of the high-pressure supply groove 69, the preceding backpressure space 77 adjacent to the downstream side of the back pressurespace 77 in the rotation direction X does not communicate with thesecond supply section 69 b simultaneously.

FIG. 8 is a graph showing changes in the pressure P33 a of thecompression chamber 33 a, the pressure P33 b of the compression chamber33 b and the pressure P77B of the back pressure space 77B in accordancewith the rotation angle of the rotor. As shown in FIG. 8, at the angleof 180 degrees, the back pressure space 77B having completedcommunication with the intermediate-pressure supply groove 67communicates with the high-pressure supply groove 69. In the presentembodiment, the high-pressure supply groove 69 is constituted by thefirst supply section 69 a and the second supply section 69 b and theback pressure space 77B communicates with the first supply section 69 aand thereafter communicates with the second supply section 69 b, alongwith rotation of the rotor 23 that rotates in the rotation direction X.

As shown by P in the graph in FIG. 17, there occurred a phenomenon inwhich the pressure in the preceding back pressure space 107 istemporarily lowered from the high pressure, by a pressure which is inthe middle of rising from the intermediate pressure of the followingnext back pressure space 107 to the high pressure. However, it ispossible to prevent occurrence of the phenomenon as shown in the graphin FIG. 8 by making the two back pressure spaces 77 not simultaneouslycommunicate with the second supply section 69 b. Accordingly, it ispossible to prevent the occurrence of chattering in which the vane 25repeats contact with and separation from the inner peripheral surface 33d of the cylinder chamber 33 by a temporary reduction of pressure in theback pressure space 77 of the vane 25 in the later stage of thecompression process and in the discharged process.

Furthermore, according to the gas compressor 1 of the presentembodiment, the total of the communication cross-sectional areas Si andS3 of the back pressure space 77 with the first supply section 69 a andthe second supply section 69 b when the communication destination of theback pressure space 77 shifts from the first supply section 69 a to thesecond supply section 69 b is set to be a minimum path cross-sectionalarea or more of the supply route of the high-pressure oil O to the firstsupply section 69 a and the second supply section 69 b.

In the middle stage of shifting the communication destination of theback pressure space 77 from the first supply section 69 a to the secondsupply section 69 b, the back pressure space 77 communicates, in theminimum path cross-sectional area or more, with at least one of thefirst supply section 69 a or the second supply section 69 b, and thusthere can be ensured a destination to which the high pressure in theback pressure space 77 is released.

Accordingly, it is possible to prevent, as shown in the graph in FIG. 8by the above-mentioned configuration, such a phenomenon as indicated byP1 in the graph in FIG. 6, namely, the phenomenon in which, in shiftingthe communication destination of the back pressure space 77 from thefirst supply section 69 a to the second supply section 69 b, thepressure in the back pressure space 77 temporarily rises by a shortageof the cross-sectional area of a route along which the high pressure inthe back pressure space 77 is released.

Thereby, there is prevented a phenomenon in which the pressing force ofthe vane 25 against the inner peripheral surface 33 d of the cylinderchamber 33 is increased more than necessary by a temporary pressureincrease in the back pressure space 77 and thus the sliding resistancebetween the both is increased. Therefore, it is possible to preventincrease in the sliding resistance of the vane 25 to the innerperipheral surface 33 d of the cylinder chamber 33 due to increase inthe power required for rotation of the rotor 23 by the temporarypressure increase in the back pressure space 77 in the later stage ofthe compression process and in the discharged process, thereby beingable to maintain the operating performance as the gas compressor 1.

Note that it is desirable that the second supply section 69 b of thehigh-pressure supply groove 69 be formed into a shape of the largestpossible size in the rotation direction X within a range in which thetwo back pressure spaces 77 mutually adjacent in the rotation directionX of the rotor 23 do not simultaneously communicate with each other.Consequently, it is possible to allow the back pressure space 77 inwhich pressure has been increased from the intermediate pressure towardthe high pressure due to communication with the first supply section 69a to communicate with the second supply section 69 b from an earlierstage of the compression process of the compression chambers 33 a, 33 band 33 c, and thereafter to stabilize the pressure in the back pressurespace 77 to the high pressure.

Accordingly, it is possible to start the discharged process of thecompression chambers 33 a, 33 b and 33 c at an earlier stage, theopen/close valve 37 of the discharge slot 35 is opened at an earlierstage and the high-pressure refrigerant in the compression chambers 33a, 33 b and 33 c is efficiently and sufficiently discharged, and therebyit is possible to achieve enhancement of refrigerant compressionefficiency.

In the present embodiment, it was assumed that the high-pressure supplygroove 69 is divided into the two mutually independent first supplysection 69 a and second supply section 69 b in the rotation direction X.However, the present invention is applicable also in a case where thehigh-pressure supply groove 69 is divided into three or more supplysections in the rotation direction X. In that case, the relation of thepresent invention is applied to the communication cross-sectional areaof an upstream-side supply section or a downstream-side supply sectionwith the back pressure space 77 when the back pressure space 77 movesstriding over the two adjacent supply sections in the rotation directionX.

Second Embodiment

Next, the second embodiment of the present invention will be describedwith reference to FIG. 9 to FIG. 15.

FIG. 9 and FIG. 10 show a structure of a vane rotary-type gas compressoraccording to the second embodiment. The gas compressor of the secondembodiment has a rear-side block 31 b 2 different from the rear-sideblock 31 b of the first embodiment. Configurations other than therear-side block 31 b 2 are the configurations that are similar to thoseof the first embodiment. The same symbols are attached to the sameconstituent points as those in the first embodiment, a descriptionthereof is omitted and only different configurations will be described.

In the present embodiment, an interval 69 c having a size that is notless than that of the back pressure space 77 of the vane groove 75 isprovided between the first supply section 69 a and the second supplysection 69 b in the rotation direction X of the rotor 23. Namely, theinterval 69 c provided between the first supply section 69 a and thesecond supply section 69 b is set larger than the width of the backpressure space 77 of the vane groove 75.

In a state shown in FIG. 11, the back pressure space 77B of the vanegroove 75 in the vane 25B which partitions the compression chamber 33 bhaving moved from the suction process to the compression process byrotation of the rotor 23 and the compression chamber 33 a which ispositioned on the downstream side of the compression chamber 33 b in therotation direction X of the rotor 23 and which has moved from thecompression process to the discharged process communicates with thefirst supply section 69 a of the high-pressure supply groove 69.

In this state, the back pressure space 77A of the vane groove 75 in thevane 25A that precedes the vane 25B in the downstream side of the vane25B in the rotation direction X of the rotor 23 has already completedcommunication with the second supply section 69 b and starts tocommunicate with the intermediate-pressure supply section 67 that ispositioned on the downstream side of the rotation direction X.

Here, there will be described the position of the interval 69 c betweenthe first supply section 69 a and the second supply section 69 b of thehigh-pressure supply groove 69 in the rotation direction X of the rotor23. When the rotor 23 rotates in the rotation direction X after thestate shown in FIG. 11, the back pressure space 77B completescommunication with the first supply section 69 a and the back pressurespace 77B communicates with the interval 69 c provided between the firstsupply section 69 a and the second supply section 69 b. At this time,there is generated a state where the back pressure space 77B is not incommunication with any of the first supply section 69 a and the secondsupply section 69 b.

In this state, when the projection stroke of the vane 25B relative tothe vane groove 75 is reduced along with rotation of the rotor 23 in therotation direction X, the volume of the back pressure space 77B isreduced. At this time, since the back pressure space 77B is not incommunication with any of the first supply section 69 a and the secondsupply section 69 b, it is not possible to release the high pressure ofthe amount corresponding to the reduced volume to them.

Accordingly, there is assumed a case where, when the vane 25B is insliding contact with a region indicated by a range (A) in FIG. 12 on theinner peripheral surface 33 d of the cylinder chamber 33, namely, theregion in which the projection stroke of the vane 25B relative to thevane groove 75 is reduced at a rate equal to or more than a constantlevel along with rotation of the rotor 23 in the rotation direction X,the interval 69 c is disposed at a position whit which the back pressurespace 77B communicates.

FIG. 12 is an explanatory diagram showing a positional relation betweenthe region in which the projection stroke of the vane 25B relative tothe vane groove 75 is reduced at a rate equal to or more than a constantlevel and the interval 69 c.

In this case, the volume of the back pressure space 77B is reduced at arate in accordance with a reduction rate of the projection stroke of thevane 25B in a state where the back pressure space 77B is isolated fromthe first supply section 69 a and the second supply section 69 b, andthe pressure in the back pressure space 77B temporarily rises asindicated by P1 in FIG. 13.

In a case where such a pressure rise of the back pressure space 77B isgenerated, the vane 25B which receives force acting in a direction ofintruding into the vane groove 75 from the inner peripheral surface 33 dof the cylinder chamber 33 attempts to project from the vane groove 75by the risen pressure in the back pressure space 77B. Then, there is apossibility that the pressing force of the vane 25B against the innerperipheral surface 33 d of the cylinder chamber 33 may be increased morethan necessary and the sliding resistance between the vane 25B and theinner peripheral surface 33 d of the cylinder chamber 33 may beincreased.

Accordingly, it is configured such that a region in which the reductionrate of the projection stroke of the vane 25 relative to the vane groove75 along with rotation of the rotor 23 in the rotation direction X onthe inner peripheral surface 33 d of the cylinder chamber 33 becomes areduction rate not more than a predetermined threshold value which islower than the above-mentioned constant rate is set as a region in whichthe reduction rate of the projection stroke is small, and the interval69 c is disposed so that the back pressure space 77 communicates withthe interval 69 c when the vane 25 comes into sliding contact with theregion in which the reduction rate of the projection stroke concerned issmall in the gas compressor 1 of the present embodiment.

Specifically, in the present embodiment, the inner peripheral surface 33d of the cylinder chamber 33 is, as shown in FIG. 14, formed so thatfour regions of:

(a) a region in which the projection stroke of the vane 25 that is insliding contact with the inner peripheral surface 33 d of the cylinderchamber 33 from the vane groove 75 is increased along with rotation ofthe rotor 23 in the rotation direction X;

(b) a region in which the projection stroke of the vane 25 that is insliding contact with the inner peripheral surface 33 d of the cylinderchamber 33 from the vane groove 75 is decreased along with rotation ofthe rotor 23 in the rotation direction X;

(c) a region in which the projection stroke of the vane 25 that is insliding contact with the inner peripheral surface 33 d of the cylinderchamber 33 from the vane groove 75 is decreased along with rotation ofthe rotor 23 in the rotation direction X and in which a reduction ratethereof is smaller than that in the region in (b); and

(d) a region in which the projection stroke of the vane 25 that is insliding contact with the inner peripheral surface 33 d of the cylinderchamber 33 from the vane groove 75 is decreased along with rotation ofthe rotor 23 in the rotation direction X and in which a reduction ratethereof is larger than that in the region in (c) and is smaller thanthat in the region in (b)

are sequentially successive in the rotation direction X of the rotor 23.

Accordingly, the interval 69 c is disposed at a position where the backpressure space 77 communicates with the interval when the vane 25 is insliding contact with the region (c) in which the reduction rate of theprojection stroke of the vane 25 along with rotation of the rotor 23 inthe rotation direction X is the smallest.

Next, an operation of the gas compressor 1 according to the presentembodiment will be described.

Also in the present embodiment, at a time point when the back pressurespace 77 having completed communication with the intermediate-pressuresupply groove 67 communicates with the first supply section 69 a of thehigh-pressure supply groove 69, the preceding back pressure space 77adjacent to the back pressure space 77 on the downstream side in therotation direction X does not communicate with the first supply section69 a simultaneously.

Accordingly, at a time point when the back pressure space 77 havingcompleted communication with the intermediate-pressure supply groove 67communicates with the first supply section 69 a of the high-pressuresupply groove 69, the preceding back pressure space 77 adjacent to theback pressure space 77 on the downstream side in the rotation directionX does not communicate with the first supply section 69 asimultaneously.

It is possible to prevent the pressure in the preceding back pressurespace 77 from being temporarily lowered from the high pressure by theintermediate pressure before the following next back pressure space 77rises to the high pressure, by allowing the two back pressure spaces 77not to communicate with the first supply section 69 a simultaneously.Accordingly, it is possible to prevent the occurrence of chattering inwhich the vane 25 repeats contact with and separation from the innerperipheral surface 33 d of the cylinder chamber 33, by a temporaryreduction of pressure in the back pressure space 77 of the vane 25 inthe early stage of the compression process.

Furthermore, the back pressure space 77 completes communication with thesecond supply section 69 b before the back pressure space 77 of the nextvane groove 75 which is positioned on the upstream side in the rotationdirection X communicates with the second supply section 69 b.Accordingly, at a time point when the back pressure space 77 havingcompleted communication with the first supply section 69 a of thehigh-pressure supply groove 69 communicates with the second supplysection 69 b of the high-pressure supply groove 69, the preceding backpressure space 77 adjacent to the downstream side of the back pressurespace 77 in the rotation direction X does not communicate with thesecond supply section 69 b simultaneously.

Accordingly, as shown in the graph in FIG. 15, it is possible to preventthe occurrence of chattering in which the vane 25 repeats contact withand separation from the inner peripheral surface 33 d of the cylinderchamber 33 by a temporary reduction of pressure in the back pressurespace 77 of the vane 25 in the later stage of the compression processand in the discharged process.

Furthermore, according to the gas compressor 1 of the presentembodiment, the interval 69 c between the first supply section 69 a andthe second supply section 69 b is positioned such that, when the backpressure space 77 communicates with the interval 69 c between the firstsupply section 69 a and the second supply section 69 b, the vane 25stored in the vane groove 75 of the back pressure space 77 comes intosliding contact with the region (c) in which the reduction rate of theprojection stroke of the vane 25 along with rotation of the rotor 23 inthe rotation direction X is the smallest.

Accordingly, when the back pressure space 77 communicates with theinterval 69 c between the first supply section 69 a and the secondsupply section 69 b, the projection stroke of the vane 25 is hardlyreduced as shown by a part surrounded by a round frame in FIG. 15 andalso the volume of the back pressure space 77 is hardly reduced.Therefore, as shown in FIG. 15, a temporary pressure increase in theback pressure space 77 is not generated when the back pressure space 77communicates with the interval 69 c.

Consequently, as indicated by P1 in the graph in FIG. 13, when thecommunication destination of the back pressure space 77 becomes theinterval 69 c between the first supply section 69 a and the secondsupply section 69 b, it is possible to prevent, as shown in the graph inFIG. 15, a phenomenon in which the releasing route for the high pressurein the back pressure space 77 is eliminated and the pressure in the backpressure space 77 temporarily rises.

Thereby, there is prevented a phenomenon in which the pressing force ofthe vane 25 against the inner peripheral surface 33 d of the cylinderchamber 33 is increased more than necessary by a temporary pressureincrease in the back pressure space 77 and thus the sliding resistancebetween the both is increased. Therefore, it is possible to preventincrease in the sliding resistance of the vane 25 to the innerperipheral surface 33 d of the cylinder chamber 33 due to increase inthe power required for rotation of the rotor 23 by the temporarypressure increase in the back pressure space 77 in the later stage ofthe compression process and in the discharged process, thereby beingable to maintain the operating performance as the gas compressor 1.

Note that it is desirable that the second supply section 69 b of thehigh-pressure supply groove 69 be formed into a shape of the largestpossible size in the rotation direction X within a range in which thetwo back pressure spaces 77 mutually adjacent in the rotation directionX of the rotor 23 do not simultaneously communicate with each other.Consequently, it is possible to allow the back pressure space 77 inwhich pressure has been increased from the intermediate pressure towardthe high pressure due to communication with the first supply section 69a to communicate with the second supply section 69 b from an earlierstage of the compression process of the compression chambers 33 a, 33 band 33 c, and thereafter to stabilize the pressure in the back pressurespace 77 to the high pressure.

Accordingly, it is possible to start the discharged process of thecompression chambers 33 a, 33 b and 33 c at an earlier stage, theopen/close valve 37 of the discharge slot 35 is opened at an earlierstage and the high-pressure refrigerant in the compression chambers 33a, 33 b and 33 c is efficiently and sufficiently discharged, and therebyit is possible to achieve enhancement of refrigerant compressionefficiency.

Note that, although, in the present embodiment, the interval 69 cprovided between the first supply section 69 a and the second supplysection 69 b is set larger than the width of the back pressure space 77of the vane groove 75, the interval 69 c may have a size smaller thanthat of the back pressure space 77 in the rotation direction X of therotor 23. In this case, when the back pressure space 77 strides over theinterval 69 c in shifting the communication destination of the backpressure space 77 from the first supply section 69 a to the secondsupply section 69 b of the high-pressure supply section 69, thecommunication cross-sectional area of the back pressure space 77 foreach of the supply sections 69 a and 69 b is reduced by an amount ofoverlapping the interval 69 c.

Since the communication cross-sectional area is reduced, when the vane25 intrudes into the back pressure space 77 side of the vane groove 75along with rotation of the rotor 23 and the volume of the back pressurespace 77 is reduced, efficiency of releasing the high pressure in theback pressure space 77 to the first supply section 69 a and the secondsupply section 69 b is reduced by the amount of the reduced volume.Then, there is a possibility that the pressure in the back pressurespace 77 may temporarily rise in the later stage of the compressionprocess and in the discharged process, the pressing force of the vane 25against the inner peripheral surface 33 d of the cylinder chamber 33 maybe increased more than necessary and the sliding resistance between thevane 25 and the inner peripheral surface 33 d of the cylinder chamber 33may be increased.

However, the interval 69 c is disposed at a position where the backpressure space 77 communicates with the interval 69 c when the vane 25is in sliding contact with the region (c) in which the reduction rate ofthe projection stroke of the vane 25 along with rotation of the rotor 23in the rotation direction X is the smallest. Therefore, there can beprevented a temporary rise in the pressure in the back pressure space 77by reduction in the releasing efficiency of the high pressure in theback pressure space 77. Accordingly, it is possible to prevent aphenomenon in which the sliding resistance of the vane 25 to the innerperipheral surface 33 d of the cylinder chamber 33 is increased by thetemporary pressure increase in the back pressure space 77 in the laterstage of the compression process and in the discharged process and thusthe power required for rotation of the rotor 23 is increased, therebybeing able to maintain the operating performance as the gas compressor1.

Note that, in the present embodiment, a region of the inner peripheralsurface 33 d of the cylinder chamber 33 with which the vane 25 comesinto sliding contact when the back pressure space 77 communicates withthe interval 69 c was determined by the use of the reduction rate of theprojection stroke of the vane 25 to the vane groove 75 as a standard. Inthe determination, an upper limit value of an allowable range of thereduction rate of the projection stroke of the vane 25 to the vanegroove 75 is determined in accordance with an allowable range for atemporary increase in pressure in the back pressure space 77.

Then, the determined upper limit value is set as a predeterminedthreshold value, and there is determined a region in which the reductionrate of the projection stroke of the vane 25 on the inner peripheralsurface 33 d of the cylinder chamber 33 becomes not more than thisthreshold value. The interval 69 c may be disposed such that, when thevane 25 comes into sliding contact with the thus determined region onthe inner peripheral surface 33 d of the cylinder chamber 33, the backpressure space 77 communicates with the interval 69 c.

By making the determination in this way, it is possible to maintain thetemporary pressure increase of the back pressure space 77 by a reductionin projection stroke of the vane 25 within the allowable range during aperiod when the back pressure space 77 is in communication with theinterval 69 c between the first supply section 69 a and the secondsupply section 69 b. Accordingly, it is possible to prevent increase inthe sliding resistance of the vane 25 to the inner peripheral surface 33d of the cylinder chamber 33 due to increase in the power required forrotation of the rotor 23 by the temporary pressure increase in the backpressure space 77 in the later stage of the compression process and inthe discharged process, thereby being able to maintain the operatingperformance as the gas compressor 1.

In the present embodiment, it has been made such that the high-pressuresupply groove 69 is divided into the two mutually independent firstsupply section 69 a and second supply section 69 b in the rotationdirection X. However, the present invention is applicable also in a casewhere the high-pressure supply groove 69 is divided into three or moresupply sections in the rotation direction X. In that case, the relationof the present invention is applied to a relative position of theinterval between the two supply sections adjacent to each other in therotation direction X and the inner peripheral surface of the cylinderchamber.

Other Embodiments

In the above-mentioned plurality of embodiments, the second supplysection 69 b of the high-pressure supply groove 69 was set to have asize at which the two back pressure spaces 77 adjacent to each other inthe rotation direction X of the rotor 23 do not communicate with eachother simultaneously. For example, the second supply section 69 b mayhave a space of a size larger than the size of the first supply section69 a in the rotation direction X. Consequently, it is possible to allowthe back pressure space 77 in which pressure has been increased from theintermediate pressure toward the high pressure due to communication withthe first supply section 69 a to communicate with the second supplysection 69 b from an earlier stage of the compression process of thecompression chambers 33 a, 33 b and 33 c, and thereafter to stabilizethe pressure in the back pressure space 77 to the high pressure.

Accordingly, it is possible to start the discharged process of thecompression chambers 33 a, 33 b and 33 c at an earlier stage, theopen/close valve 37 of the discharge slot 35 is opened at an earlierstage and the high-pressure refrigerant in the compression chambers 33a, 33 b and 33 c is efficiently and sufficiently discharged, and therebyit is possible to achieve enhancement of refrigerant compressionefficiency.

In addition, in the above-mentioned plurality of embodiments, adescription has been made by taking, by way of example, a case ofdividing the high-pressure supply groove 69 into two of the first supplysection 69 a and the second supply section 69 b in the rotationdirection X in order to prevent the back pressure space 77 of the vane25 from communicating with the same supply section as that of the backpressure space 77 of the upstream-side vane 25 by way of example.However, the present invention is also widely applicable to a case wherethe high-pressure supply groove 69 is divided into three or more supplysections in the rotation direction X.

In that case, it is possible to obtain the similar effects to those ofthe above-mentioned plurality of embodiments by forming, among the threeor more supply sections, one supply section that communicates with theback pressure space 77 that is in a state where the pressure in the backpressure space 77 is in the middle of rising from the intermediatepressure to the high pressure, into a shape in which the two backpressure spaces 77 adjacent to each other in the rotation direction X donot communicate with each other simultaneously.

Namely, the supply section positioned second from the most upstream sideof the rotation direction X becomes at least an object to be formed intoa shape in which the two back pressure spaces 77 adjacent to each otherin the rotation direction X do not communicate with each othersimultaneously. In addition, also each of the third and subsequentsupply sections from the most upstream side becomes the object to beformed into a shape in which the two back pressure spaces 77 adjacent toeach other in the rotation direction X do not communicate with eachother simultaneously, in a case of communicating with the back pressurespace 77 when the pressure of the back pressure space 77 is in themiddle of rising from the intermediate pressure to the high pressure.

The above embodiments of the present invention are merely illustrativeones which have been described for facilitating understanding of thepresent invention and the present invention is not limited to theembodiments concerned. The technical scope of the present inventionincludes, not limited to specific technical matters disclosed in theabove-mentioned embodiments, various modifications, changes, alternativetechnologies and the like, which can be easily derived therefrom.

The present application claims the priority based on Japanese PatentApplication No. 2014-260491 filed on Dec. 24, 2014, based on JapanesePatent Application No. 2014-260492 filed on Dec. 24, 2014 and based onJapanese Patent Application No. 2014-260500 filed on Dec. 24, 2014, theentire contents of which are incorporated herein by reference.

INDUSTRIAL APPLICABILITY

According to the present invention, the back pressure space of the vanegroove having completed communication with the intermediate-pressuresupply section communicates with the first supply section of thehigh-pressure supply section until the refrigerant pressure in each ofthe compression chambers having been partitioned by the vane stored inthe vane groove reaches the highest pressure, and then the high pressureis supplied from the first supply section. Thereafter, this backpressure space completes communication with the first supply sectionbefore the back pressure space of the next vane groove on the upstreamside of the rotation direction communicates with the first supplysection, and then communicates with the next second supply section thatis independent of the first supply section and subsequently the highpressure is again supplied thereto.

Accordingly, at a time point when the back pressure space havingcompleted communication with the intermediate-pressure supply sectioncommunicates with the first supply section of the high-pressure supplysection, the preceding back pressure space which is adjacent to the backpressure space on the downstream side in the rotation direction does notcommunicate with the first supply section simultaneously. Consequently,the pressure in the preceding back pressure space is prevented frombeing temporarily lowered from the high pressure by the intermediatepressure of the following next back pressure space and the occurrence ofchattering of the vane by a temporary reduction in pressure in the backpressure space of the vane can be prevented.

REFERENCE SIGNS LIST

-   -   1 gas compressor    -   2 housing    -   3 compression section    -   4 motor section    -   5 inverter section    -   7 front head    -   9 rear case    -   11 suction chamber    -   13 inner wall    -   15, 108 discharge chamber    -   19 compression block    -   21 oil separator    -   23, 102 rotor    -   23 a outer peripheral surface    -   25 (25A, 25B, 25C), 103 vane    -   27 drive shaft    -   29, 100 cylinder block    -   31, 101 side block    -   31 a front-side block    -   31 b rear-side block    -   33, 105 cylinder chamber    -   33 a, 33 b, 33 c, 105 a, 105 b, 105 c compression chamber    -   33 d inner peripheral surface    -   35 discharge slot    -   37, 109 open/close valve    -   39 suction slot    -   41 cylinder-side oil supply path    -   43 front-side end surface    -   47 front-side bearing    -   49 front-side oil supply path    -   51, 113 intermediate-pressure supply groove    -   53, 114 high-pressure supply groove    -   55 front-side annular groove    -   57 rear-side end surface    -   59 oil supply hole    -   59 a rear-side oil supply path    -   59 b rear-side oil supply path    -   61 discharge hole    -   63 rear-side bearing    -   65 rear-side communication path    -   67 intermediate-pressure supply groove (intermediate-pressure        supply section)    -   69 high-pressure supply groove (high-pressure supply section)    -   69 a first supply section (upstream-side supply section)    -   69 b second supply section (downstream-side supply section)    -   69 c interval    -   71 a, 71 b high-pressure supply path    -   73 rear-side annular groove    -   75, 106 vane groove    -   77 (77A, 77B, 77C), 107 back pressure space    -   79 stator    -   81 motor rotor    -   110 suction port    -   O oil    -   X rotation direction

1.-5. (canceled)
 6. A gas compressor comprising: a tubular cylinderblock having therein a cylinder chamber in which a refrigerant iscompressed; side blocks that are attached to side parts of the cylinderblock and seal an opening of the cylinder chamber on the side parts; arotor that rotates in the cylinder chamber and has a plurality of vanegrooves opening to an outer peripheral surface facing an innerperipheral surface of the cylinder chamber at intervals in a rotationdirection; a plurality of vanes that is respectively stored in therespective vane grooves, protrudes and retracts from the outerperipheral surface, comes into sliding contact with the inner peripheralsurface of the cylinder chamber, and partitions a space between theinner peripheral surface and the outer peripheral surface of the rotorinto a plurality of compression chambers; an intermediate-pressuresupply section that is formed in at least one of the side blocks,communicates with a back pressure space at a groove bottom of each ofthe vane grooves storing the vanes for partitioning the compressionchambers from a suction process to a compression process, and supplies,to the back pressure space, an intermediate pressure larger than arefrigerant pressure in each of the compression chambers from thesuction process to the compression process; and a high-pressure supplysection that is formed in at least one of the side blocks, communicateswith the back pressure space in each of the vane grooves storing thevanes for partitioning the compression chambers from the compressionprocess to a discharged process after communication with theintermediate-pressure supply section has been completed, and supplies,to the back pressure space, high pressure larger than the refrigerantpressure in each of the compression chambers from the compressionprocess to the discharged process and larger than the intermediatepressure, wherein the high-pressure supply section is divided into aplurality of mutually independent supply sections in the rotationdirection, the second supply section that is positioned at leastsecondarily from the most upstream side in the rotation direction isformed into a shape in which the second supply section, whilecommunicating with the back pressure space of one vane groove, does notsimultaneously communicate with the back pressure space of the othervane groove adjacent to the vane groove on the upstream side in therotation direction, and the high-pressure supply section is formed in arange in which it simultaneously communicates with the back pressurespace of the one vane groove and the back pressure space of the othervane groove adjacent to the vane groove on the upstream side in therotation direction.
 7. The gas compressor according to claim 6, whereinthe upstream-side supply section and the downstream-side supply sectionwhich are mutually adjacent in the rotation direction have, in therotation direction, an interval at which, when the back pressure spacecommunicates with the upstream-side supply section and thedownstream-side supply section in a striding manner, a total ofcommunication cross-sectional areas with the respective supply sectionsbecomes at least a minimum path cross-sectional area of high-pressuresupply paths for supplying high pressures respectively to the respectivesupply sections.
 8. The gas compressor according to claim 6, wherein theupstream-side supply section and the downstream-side supply section aredisposed at an interval in the rotation direction, and the interval isdisposed at a position communicating with the back pressure space at arotation position of the rotor where a reduction rate of a projectionstroke of the vane relative to the vane groove becomes not more than apredetermined threshold value.
 9. The gas compressor according to claim8, wherein the inner peripheral surface of the cylinder chamber isformed so that: (a) a region in which the projection stroke of the vanethat is in sliding contact with the inner peripheral surface from thevane groove is increased along with rotation of the rotor in therotation direction; (b) a region in which the projection stroke of thevane that is in sliding contact with the inner peripheral surface fromthe vane groove is decreased along with rotation of the rotor in therotation direction; (c) a region in which the projection stroke of thevane that is in sliding contact with the inner peripheral surface fromthe vane groove is decreased along with rotation of the rotor in therotation direction and in which a reduction rate thereof is smaller thanthat in the region in (b); and (d) a region in which the projectionstroke of the vane that is in sliding contact with the inner peripheralsurface from the vane groove is decreased along with rotation of therotor in the rotation direction and in which a reduction rate thereof islarger than that in the region in (c) and is smaller than that in theregion in (b) are sequentially successive in the rotation direction, andwherein the interval is disposed at a position communicating with theback pressure space of the vane groove storing the vane when the vane isin sliding contact with the region in (c) on the inner peripheralsurface.
 10. The gas compressor according to claim 6, wherein the secondsupply section has a space of a size that is larger in the rotationdirection than a size of the first supply section positioned on theupstream side of the second supply section in the rotation direction.